The present invention relates to a filter arrangement having at least two filter chambers which can be alternately impinged upon by activation of a reversing valve. The reversing valve can be set in the corresponding suitable positions upon rotation. The rotatable valve part is connected with a reversing lever having a manually operable handle part. A compensation valve can be activated to provide pressure compensation between the filter chambers. A detent device can be converted into a locking position blocking the rotary movement of the valve part and dependent upon activation of the compensation valve can be converted into a release position permitting the rotary movement of the valve part.
Facilitating activation of a filter arrangement using only one hand is intended to avoid requiring that the operator to use both hands to activate the reversing procedure, which two-handed procedure involves one hand to rotate ht reversing lever and a second hand to hold the detent device in the release setting. A filter arrangement allowing one-handed reversal is disclosed in DE 40 11 419 C2. An operating member of the detent device is mounted movably on the reversing lever such that, with gripping of the handle part of the reversing lever, this operating member can be engaged simultaneously with the engagement of the handle part of the reversing lever and can be moved into the position corresponding with the release position of the detent device.
With this previously disclosed filter arrangement, the advantage of the possibility of one-hand manual activation must be purchased at the cost of the involvement of the necessary, but cumbersome, structure of the reversing lever. On the handle part of the reversing lever, the activation member of the detent device is arranged movably as an additional structural part and is pre-biased by a spring arrangement in the position corresponding to the detent or locking position of the detent device.
Objects of the present invention are to provide a filter arrangement having a simplified structure that can be operated to reverse with the operator using only one hand.
The foregoing objects are attained with a filter arrangement having a reversing lever constructed in the form of a double-armed pivot lever and mounted on the valve part with its pivot axis perpendicular to its rotary axis. In this manner, its lever arm part more distant from the handle part, during the pivot movement, impinges upon the compensation valve. The second lever arm forming the handle part during the pivot movement of the reversing lever activating the compensation valve converts or moves the detent device out of the locking position into the release position.
The two-armed pivot lever is provided as reversing lever. This pivot lever is connected with the valve part of the reversing valve upon rotation, and is pivotally movable relative to the valve part. The reversing lever, although it represents a structure of solely one part, performs three functions. These functions include first of all the reversing function for the reversing valve by rotation of its valve part. Secondly, the pivot movement occurring relative to the valve part causes the reversing lever with the second lever arm forming the handle part to unlock and release the detent device. Simultaneously, as a third function, the other lever arm activates the compensation valve. In other words, the present invention allows activation using one single hand as a result of the one-part construction of the reversing lever, including, without requiring, a movably arranged, spring-biased activation member thereon. This sort of member is required in the conventional filter arrangement for cooperation with the detent device arrangement and with the compensation valve.
In one preferred exemplary embodiment, the detent device has a detent stud projecting outward toward the housing of the filter arrangement. The stud engages force-locking in both of the positions of the reversing valve in each case in a complementary facing detent notch. The detent notch is constructed on the filter housing. In the case of pivotal movement of the reversing lever activating the compensation valve, the detent stud comes free from the relevant facing detent notch.
Preferably, the arrangement, for the activation of the compensation valve, the lever arm of the reversing lever which is more distant from the handle part bears upon a valve tamping rod of the compensation valve. The tamping rod can be pre-biased for force-locking engagement with the associated lever arm of the reversing lever by a spring arrangement. The reversing lever is pushed by the spring arrangement simultaneously in the pivotal position corresponding to the detent lock position of the detent device.